Re: Query much slower when run from postgres function

Mario Splivalo <mario.splivalo@megafon.hr> writes:
> So, it is the same. When I do EXPLAIN ANALYZE EXECUTE I get completely
> different execution plan:
> ...
>                      ->  Bitmap Heap Scan on messages
> (cost=287.98..21192.42 rows=12848 width=4) (actual time=0.049..0.169
> rows=62 loops=1)
>                            Recheck Cond: (service_id = $1)
>                            ->  Bitmap Index Scan on
> messages_uq__service_id__tan  (cost=0.00..284.77 rows=12848 width=0)
> (actual time=0.038..0.038 rows=62 loops=1)
>                                  Index Cond: (service_id = $1)

Well, there's the problem: without knowing what the specific service_id
is, the planner is estimating 12848 matching rows, which is evidently
off by a couple of orders of magnitude.  And that's pushing it to adopt
a hash join instead of a nestloop.  Are you sure the stats on this
table are up to date?  Maybe you need to increase the stats target?

            regards, tom lane